The state of the art referring to fire guns, more specifically pistols, has for long incorporated various projects of firing devices, each one with its particularities. These firing devices can be divided in specific groups according to the mode of operation of the pistol, such as: single action (SA); double action (DA); or mixed (DA/SA), i.e. they can operate both in the single action mode and the double action mode, depending on the positioning of a given mechanical element of control, usually some kind of a side key on the pistol body. No matter which is the mode of operation, a common characteristic to all these pistols is the presence of a specific project and/or device for each one. However, we are unaware of a pistol or a firing device for a pistol, which optimizes its production, so as to enable the manufacture of models with different modes of operation, but with similar characteristics of operation/components.